The first enuresis alarm was introduced in 1904 with the goal of signaling the need for change of bedclothes to staff on the pediatric ward, and an unexpected therapeutic effect was observed in older children with nocturnal enuresis.¹ Since that time, many iterations of enuresis alarms, including “bell and pad alarms” with a mat placed under the patient with moisture sensor, body-worn alarms in which a sensor is placed in the child’s undergarments, and even code-word alarms, in which a pre-recorded code word is given to the child when the alarm goes off and the child is encouraged to remember the word the next morning, have been studied.² There is not an established gold standard, but alarms are now considered first-line treatment for primary monosymptomatic nocturnal enuresis (PMNE) by the International Children’s Continence Society (ICCS).³ Mechanisms of action for alarms are incompletely understood, and various types of behavioral conditioning, conditioned muscle response of the urethral sphincter, increased functional bladder capacity, increased antidiuretic hormone production, and a maturational delay of central reflex control have been postulated.⁴ Behavioral interventions, including random nighttime waking, have also been studied, but there is no high-quality evidence suggesting that waking at random intervals leads to cure of nocturnal enuresis. We sought to determine if manual nighttime waking in addition to a traditional moisture sensor alarm would lead to benefit in treatment of children with PMNE.

Figure 1. Mean proportion of wet nights over time in each group.

We recruited patients with diagnosis of PMNE as determined by ICCS criteria and Vancouver Symptom Scores at the University of Iowa Pediatric Urology clinic and randomized them to the traditional moisture alarm versus a “manual trigger” plus moisture alarm group. Members of each group were given an identical Wet-Stop 3+ wearable alarm (donated by Potty MD, Knoxville, Tennessee). In both groups, subjects and parents completed a nightly diary of enuresis events and alarm usage. In the manual group, in addition to using in the traditional fashion, parents were instructed to trigger the alarm via an embedded switch in the device 1 to 2 hours after bedtime. Logging was continued until subjects no longer wished to continue or until the child experienced 14 consecutive dry nights or 27 nonconsecutive dry nights over a 30-day period, considered cure.

Figure 2. Kaplan-Meier curves and 95% confidence intervals for the probability of continued bedwetting over time by group when continued bedwetting is defined as not being cured.

We enrolled 117 children, with 61 of those completing diaries sufficient to analyze outcomes. Median age was 8.4 years (IQR 7.2–10.8), and 75% of subjects were males. Overall trends were favorable for the manual trigger group but differences were not statistically significant. The overall rate of cure in the traditional group was 54% and 62% in the manual trigger group. Reduction to at least 50% of dry nights was 87% versus 96%, respectively. Figure 1 shows mean proportion of wet nights per week in each group. Mean time to cure was 8.2 weeks (range 3–22) in the traditional group and 7.0 weeks (range 3–11) in the manual trigger group. Figure 2 shows the Kaplan-Meier curves showing the probability of continued bedwetting over time between groups. The average time to a 50% reduction in the proportion of wet nights was about 4 weeks for both groups. Over the first 10 weeks, the probability of continued bedwetting decreased at a similar rate in both groups, but after week 10 we observed a lower probability of continued wetting in the manual trigger group.

Although cure and time to cure were more favorable in the manual trigger plus moisture alarm group, no statistically significant differences were demonstrated. It is possible that the study was underpowered to demonstrate a clinically significant difference, so a larger or multi-institutional cohort may prove different. The rigorous diary-keeping allowed for us to not only obtain information about rates of cure but also exact time to cure. Overall success rate of 57%, mean time to reduction in 50% of wet nights of 3.9 weeks, and mean time to cure of 7.6 weeks is valuable information for families considering undertaking enuresis alarm treatment.